RESUMO
The design, synthesis, and structure activity relationships for a novel series of indoles as potent, selective, thyroid hormone receptor ß (TRß) agonists is described. Compounds with >50× binding selectivity for TRß over TRα were generated and evaluation of compound 1c from this series in a model of dyslipidemia demonstrated positive effects on plasma lipid endpoints in vivo.
Assuntos
Acetatos/farmacologia , Desenho de Fármacos , Indóis/farmacologia , Receptores beta dos Hormônios Tireóideos/agonistas , Acetatos/síntese química , Acetatos/química , Relação Dose-Resposta a Droga , Humanos , Indóis/síntese química , Indóis/química , Modelos Moleculares , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
Recent studies have found that glucose-dependent insulinotropic polypeptide receptor (GIPR) agonism can enhance the metabolic efficacy of glucagon-like peptide-1 receptor agonist treatment by promoting both weight-dependent and -independent improvements on systemic insulin sensitivity. These findings have prompted new investigations aimed at better understanding the broad metabolic benefit of GIPR activation. Herein, we determined whether GIPR agonism favorably influenced the pharmacologic efficacy of the insulin-sensitizing thiazolidinedione (TZD) rosiglitazone in obese insulin-resistant (IR) mice. Genetic and pharmacological approaches were used to examine the role of GIPR signaling on rosiglitazone-induced weight gain, hyperphagia, and glycemic control. RNA sequencing was conducted to uncover potential mechanisms by which GIPR activation influences energy balance and insulin sensitivity. In line with previous findings, treatment with rosiglitazone induced the mRNA expression of the GIPR in white and brown fat. However, obese GIPR-null mice dosed with rosiglitazone had equivalent weight gain to that of wild-type (WT) animals. Strikingly, chronic treatment of obese IR WT animals with a long-acting GIPR agonist prevented rosiglitazone-induced weight-gain and hyperphagia, and it enhanced the insulin-sensitivity effect of this TZD. The systemic insulin sensitization was accompanied by increased glucose disposal in brown adipose tissue, which was underlined by the recruitment of metabolic and thermogenic genes. These findings suggest that GIPR agonism can counter the negative consequences of rosiglitazone treatment on body weight and adiposity, while improving its insulin-sensitizing efficacy at the same time.
Assuntos
Resistência à Insulina , Receptores dos Hormônios Gastrointestinais , Tiazolidinedionas , Camundongos , Animais , Insulina/metabolismo , Resistência à Insulina/fisiologia , Rosiglitazona/uso terapêutico , Obesidade/metabolismo , Tiazolidinedionas/uso terapêutico , Receptores dos Hormônios Gastrointestinais/metabolismo , Aumento de Peso , Insulina Regular Humana/uso terapêutico , Hiperfagia , Polipeptídeo Inibidor Gástrico/farmacologiaRESUMO
Tirzepatide, a glucose-dependent insulinotropic polypeptide/glucagon-like peptide 1 receptor (GIPR/GLP-1R) agonist, has, in clinical trials, demonstrated greater reductions in glucose, body weight, and triglyceride levels compared with selective GLP-1R agonists in people with type 2 diabetes (T2D). However, cellular mechanisms by which GIPR agonism may contribute to these improved efficacy outcomes have not been fully defined. Using human adipocyte and mouse models, we investigated how long-acting GIPR agonists regulate fasted and fed adipocyte functions. In functional assays, GIPR agonism enhanced insulin signaling, augmented glucose uptake, and increased the conversion of glucose to glycerol in a cooperative manner with insulin; however, in the absence of insulin, GIPR agonists increased lipolysis. In diet-induced obese mice treated with a long-acting GIPR agonist, circulating triglyceride levels were reduced during oral lipid challenge, and lipoprotein-derived fatty acid uptake into adipose tissue was increased. Our findings support a model for long-acting GIPR agonists to modulate both fasted and fed adipose tissue function differentially by cooperating with insulin to augment glucose and lipid clearance in the fed state while enhancing lipid release when insulin levels are reduced in the fasted state.
Assuntos
Adipócitos , Polipeptídeo Inibidor Gástrico , Receptores dos Hormônios Gastrointestinais , Animais , Humanos , Masculino , Camundongos , Adipócitos/metabolismo , Adipócitos/efeitos dos fármacos , Polipeptídeo Inibidor Gástrico/metabolismo , Polipeptídeo Inibidor Gástrico/farmacologia , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Receptor do Peptídeo Semelhante ao Glucagon 2 , Glucose/metabolismo , Insulina/metabolismo , Lipólise/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Nutrientes/metabolismo , Obesidade/metabolismo , Obesidade/tratamento farmacológico , Receptores dos Hormônios Gastrointestinais/metabolismo , Receptores dos Hormônios Gastrointestinais/agonistas , Transdução de Sinais/efeitos dos fármacos , Triglicerídeos/metabolismoRESUMO
Tirzepatide (LY3298176), a dual GIP and GLP-1 receptor (GLP-1R) agonist, delivered superior glycemic control and weight loss compared with GLP-1R agonism in patients with type 2 diabetes. However, the mechanism by which tirzepatide improves efficacy and how GIP receptor (GIPR) agonism contributes is not fully understood. Here, we show that tirzepatide is an effective insulin sensitizer, improving insulin sensitivity in obese mice to a greater extent than GLP-1R agonism. To determine whether GIPR agonism contributes, we compared the effect of tirzepatide in obese WT and Glp-1r-null mice. In the absence of GLP-1R-induced weight loss, tirzepatide improved insulin sensitivity by enhancing glucose disposal in white adipose tissue (WAT). In support of this, a long-acting GIPR agonist (LAGIPRA) was found to enhance insulin sensitivity by augmenting glucose disposal in WAT. Interestingly, the effect of tirzepatide and LAGIPRA on insulin sensitivity was associated with reduced branched-chain amino acids (BCAAs) and ketoacids in the circulation. Insulin sensitization was associated with upregulation of genes associated with the catabolism of glucose, lipid, and BCAAs in brown adipose tissue. Together, our studies show that tirzepatide improved insulin sensitivity in a weight-dependent and -independent manner. These results highlight how GIPR agonism contributes to the therapeutic profile of dual-receptor agonism, offering mechanistic insights into the clinical efficacy of tirzepatide.
Assuntos
Tecido Adiposo Branco/metabolismo , Polipeptídeo Inibidor Gástrico/farmacologia , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Resistência à Insulina , Obesidade/metabolismo , Tecido Adiposo Branco/patologia , Aminoácidos de Cadeia Ramificada/genética , Aminoácidos de Cadeia Ramificada/metabolismo , Animais , Peso Corporal/efeitos dos fármacos , Peso Corporal/genética , Receptor do Peptídeo Semelhante ao Glucagon 1/genética , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Camundongos , Camundongos Knockout , Obesidade/tratamento farmacológico , Obesidade/genética , Obesidade/patologiaRESUMO
The absence of insulin results in oscillating hyperglycemia and ketoacidosis in type 1 diabetes. Remarkably, mice genetically deficient in the glucagon receptor (Gcgr) are refractory to the pathophysiological symptoms of insulin deficiency, and therefore, studies interrogating this unique model may uncover metabolic regulatory mechanisms that are independent of insulin. A significant feature of Gcgr-null mice is the high circulating concentrations of GLP-1. Hence, the objective of this report was to investigate potential noninsulinotropic roles of GLP-1 in mice where GCGR signaling is inactivated. For these studies, pancreatic ß-cells were chemically destroyed by streptozotocin (STZ) in Gcgr(-/-):Glp-1r(-/-) mice and in Glp-1r(-/-) animals that were subsequently treated with a high-affinity GCGR antagonist antibody that recapitulates the physiological state of Gcgr ablation. Loss of GLP-1 action substantially worsened nonfasting glucose concentrations and glucose tolerance in mice deficient in, and undergoing pharmacological inhibition of, the GCGR. Further, lack of the Glp-1r in STZ-treated Gcgr(-/-) mice elevated rates of endogenous glucose production, likely accounting for the differences in glucose homeostasis. These results support the emerging hypothesis that non-ß-cell actions of GLP-1 analogs may improve metabolic control in patients with insulinopenic diabetes.
Assuntos
Glucagon/metabolismo , Glucose/metabolismo , Insulina/metabolismo , Receptores de Glucagon/deficiência , Animais , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Receptor do Peptídeo Semelhante ao Glucagon 1 , Imuno-Histoquímica , Camundongos , Camundongos Knockout , Receptores de Glucagon/antagonistas & inibidores , Receptores de Glucagon/genética , Receptores de Glucagon/metabolismo , Estreptozocina/farmacologiaRESUMO
Young mice tolerate myocardial loss after coronary artery ligation (CAL) without congestive heart failure (CHF) signs or mortality. We predicted a CHF phenotype after CAL in aged mice. Left coronary artery ligation produced permanent myocardial infarcts (MI). Mortality was higher in male 14-mo-old C57BL/6N mice (Older mice) than in 2-mo-old mice (Young mice) (16 of 25 Older mice died vs. 0 of 10 Young mice, P < 0.02). After 8 wk, rales, weight loss, and lethargy preceded deaths. Captopril (50 mg x kg(-1) x day(-1)) increased Older mouse survival (6 of 22 died, P < 0.02). Captopril improved systolic function (peak aortic blood velocity) from 76 +/- 6% of baseline in untreated Older mice to 93 +/- 8% (P < 0.036). At 24 h, MI comprised 28 +/- 4% of the left ventricle in Young mice, surprisingly larger than that in Older mice (18 +/- 2%, P < 0.011). Endocardial area underlying the infarct scar was significantly larger in Older mice than in Young mice. Captopril did not reduce expansion but markedly reduced septal hypertrophy. Aging reduces compensatory ability in mice despite smaller acute infarcts. Less effective myocardial repair, greater infarct expansion, and septal hypertrophy are seen with aging. Aging is a more relevant murine model of post-MI heart failure in patients.